(x - 9)^2 = 81. Literally 90% got it wrong!

Hinzugefügt: 2026-05-05

[00:00:00]Welcome everyone. So, yes, literally everyone thought that the answer for this one was supposed to be just six.

[00:00:07]6 minus 2 Sorry.

[00:00:09]Sorry, my bad. A lot of everyone thought that the answer for this one was supposed to be what? Four. 4 minus 2 the whole square should get you 2 squared which gets you four. This is correct.

[00:00:20]One of the answers is correct, but since the degree of the entire equation is two, there's a very high chance that we will have another value of x as well.

[00:00:29]Now, whenever there is an square involving a variable, okay, and you want to take square roots on both sides, the value of that square root comes in positive and negative values, okay? Because there is a variable involved.

[00:00:44]So, now I can say my x minus 2 is equal to either 2 or I can say x minus 2 is equal to minus 2.

[00:00:53]When you add two on both sides, you get the value of x over here as four. And here, you get the value of x as nothing but zero.

[00:01:03]Okay? So, now like we saw that four is absolutely correct, but let's see for zero. 0 minus 2 the whole square. That gets you minus 2 the whole square. Now, square of a negative number still gets you a positive value. So, here we can say the value of x is either four or zero. I hope this is very, very clear to everyone. That's it for today. I will see you in the next video.